Solid electrolyte cells have been used in the electronic industry for apparatus relating to aviation, measurement and control apparatus. Such cells are desirable because they have long shelf life, less leakage of internal solvents, high generating voltage per cell and thus are easy to laminate.
However, a conventional solid electrolyte cell with .beta.-alumina of Na.sup.+ ion conduction type is used only above the temperature of 200.degree.C, because the electric conductivity of the solid electrolyte is low at the room temperature and polarisation is large.
This gives rise to many difficult problems, such as: oxidization of anodic active material; treatment and design for preventing corrosion of cans and the solid electrolyte; and choice of materials for heat-resistant sealing of the cans.
Furthermore, since cathodic active material and anodic active material are used in the molten state, a heating device must be supplied. Because of these problems, the use of such cells is inconvenient and is not necessarily safe.